In a networked environment such as the Internet, entities such as companies can provide information for display on web pages. The web pages can include text, video, or audio information provided by the entities via a web page server. Additional or alternative content items such as advertisements may be provided by third parties (such as advertisers) for display on the web pages together with the main content. Thus, a user viewing a web page can access the information that is the subject of the web page, as well as third party advertisements that may or may not be related to the subject matter of the web page.